听力原文：

Man: How many different countries do you think you've been to? 

Woman: Once I made a count of how many countries I'd hitchhiked through and it came to twenty-eight. So if you add on a few more for those where I haven't hitched, I imagine it comes to about forty by now.

Man: About forty! 

本题考查这位女士去过几个国家。

由听力原文：

男:你觉得你去过多少个不同的国家?
女:有一次我数了一下搭便车经过的国家，一共是28个。所以如果你再给那些我还没搭便车的，我想现在已经有40个了。

男:大约四十!

可知C项符合题意。